Extent of road lighting impact on highway capacity

Abstract

As roads are very scarce and costly to build, it is needed to use their maximum capacity at a reasonable serviceability. Clearly, to achieve this goal, roadways should be studied in different conditions in order to provide certain facilities. This study examines the impact of road lighting on roadway capacity during night-time under the road lightings and to compare to its original capacity when there is natural day light. Data for this study was collected from a two-lane urban highway “5” near Universiti Teknologi Malaysia in Johor state of Malaysia. A pneumatic loop detector was installed for 3 weeks to record volume and speed of the traffic 24 hour. The data was filtered to avoid adverse weather conditions and congestions. Data related to off-peak uncongested conditions during daylight and lighting were analysed to see the effect of road lighting. Capacity of study route estimated 2665 pc/h/ln during daylight. In addition, during lighting hours, maximum flow is estimated 2364 pc/h/ln which is approximately 11% reduction compare to daylight. Meanwhile free-flow speed and optimum speed computed during study and results show minor changes. Free-flow speed and optimum speed computed 85 km/h and 42 km/h, respectively, for both daylight and lighting hours.